The interaction of thermal radiation and water mist in fire suppression

Water mist is a highly effective fire-protection agent. In addition to the direct interaction of evaporating droplets with a flame to cause weakening or extinction, the mist serves to scatter and absorb thermal radiation. The central objective of this paper is to characterize the interaction of the water mist with thermal radiation. The droplet cloud can absorb thermal radiation, especially in the wavelengths associated with water bands. The radiation serves to preheat and pre-evaporate the droplets upstream of the flame itself, altering the structure and extinction of the flame. The mist also acts as a radiation shield that attenuates radiation. The radiative characteristics of the mist depend strongly on droplet size and number density. Spectrally dependent gas-phase emission and absorption is modeled using an exponential wide-band model and radiation-droplet interaction is modeled using Mie-scattering theory. Radiative transfer in the mist is described with a two-flux model.